Blood Pressure Over-Shoot Due to Acute Clonidine (Catapres) Withdrawal: Studies on Arterial and Urinary Catecholamines and Suggestions for Management of the Crisis

1973 ◽  
Vol 45 (s1) ◽  
pp. 181s-183s
Author(s):  
Lennart Hansson ◽  
Stephen N. Hunyor
Keyword(s):  
Blood Pressure ◽  
Pressure Rise ◽  
Withdrawal Symptoms ◽  
Adrenergic Blockade ◽  
Urinary Catecholamines ◽  
Hypertensive Patients ◽  
Arterial Blood ◽  
Blood Pressure Rise ◽  
Catecholamines In Urine ◽  
Cessation Of Treatment

1. Clonidine was withdrawn acutely in five hypertensive patients with a documented blood pressure over-shoot after previous temporary cessation of treatment. 2. In all patients a severe rise of systolic and diastolic blood pressure was seen (average 67/58 mmHg). This was accompanied by a number of ‘withdrawal symptoms’, e.g. restlessness, tremor, headaches and nausea. 3. Catecholamines in urine rose from 32 μg/l to 112 μg/l (001 < P < 0.02) and in arterial blood from 0.52 μg/l to 1.0 μg/l (not significant). 4. The crisis could be reversed acutely by α- and β-adrenergic blockade. 5. Catecholamine depletion with reserpine before the withdrawal of clonidine seemed to reduce the blood pressure rise and the withdrawal symptoms.

Some effects of apneic underwater diving on blood gases, lactate, and pressure in man

1962 ◽  
Vol 17 (6) ◽  
pp. 938-942 ◽  
Author(s):  
C. Robert Olsen ◽  
Darrell D. Fanestil ◽  
Per F. Scholander
Keyword(s):  
Carbon Dioxide ◽  
Blood Pressure ◽  
Heart Rate ◽  
Pressure Rise ◽  
Blood Gases ◽  
Breath Holding ◽  
Blood Oxygen ◽  
Arterial Blood ◽  
Blood Pressure Rise ◽  
Arterial Blood Oxygen

Five men of outstanding diving ability performed apneic underwater dives in a specially fitted tank. The divers hyperventilated to extreme degrees of hypocapnia before submerging, and their arterial blood carbon dioxide tensions rarely rose above normal levels during a dive. Arterial blood oxygen content was 15.5 vol % or above at the end of two 3-min resting dives and of three 1.5-min exercise dives. Blood lactate concentrations increased during the latter half of exercise dives and reached peak values after surfacing. A rise in arterial blood pressure began by 10 sec in each dive and persisted, coincident with a falling heart rate, to the end of the dive. The rate of blood pressure rise was greater during a dive in water of 26 C than with breath holding by the same subject out of water. Some differences between the adaptations of diving men and of other diving mammals are briefly discussed. Submitted on April 2, 196

Enhancement of the Antihypertensive Effect of Hydrochlorothiazide in Dogs after Suppression of Renin Release by Beta-Adrenergic Blockade

1975 ◽  
Vol 48 (2) ◽  
pp. 147-151
Author(s):  
C. S. Sweet ◽  
M. Mandradjieff
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Arterial Blood Pressure ◽  
Antihypertensive Effect ◽  
Plasma Renin ◽  
Renin Activity ◽  
Renin Release ◽  
Antihypertensive Activity ◽  
Adrenergic Blockade ◽  
Arterial Blood

1. Renal hypertensive dogs were treated with hydrochlorothiazide (8−2 μmol/kg or 33 μmol/kg daily for 7 days), or timolol (4.6 μmol/kg daily for 4 days), a potent β-adrenergic blocking agent, or combinations of these drugs). Changes in mean arterial blood pressure and plasma renin activity were measured over the treatment period. 2. Neither drug significantly lowered arterial blood pressure when administered alone. Plasma renin activity, which did not change during treatment with timolol, was substantially elevated during treatment with hydrochlorothiazide. 3. When timolol was administered concomitantly with hydrochlorothiazide, plasma renin activity was suppressed and blood pressure was significantly lowered. 4. These observations suggest that compensatory activation of the renin-angiotensin system limits the antihypertensive activity of hydrochlorothiazide in renal hypertensive dogs and suppression of diuretic-induced renin release by timolol unmasks the antihypertensive effect of the diuretic.

Arterial blood pressure responses to graded transient arousal from sleep in normal humans

1993 ◽  
Vol 74 (3) ◽  
pp. 1123-1130 ◽  
Author(s):  
R. J. Davies ◽  
P. J. Belt ◽  
S. J. Roberts ◽  
N. J. Ali ◽  
J. R. Stradling
Keyword(s):  
Blood Pressure ◽  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Confidence Interval ◽  
Rem Sleep ◽  
High Frequency ◽  
Pressure Rise ◽  
Nrem Sleep ◽  
Blood Pressure Rise ◽  
Obstructive Sleep

During obstructive sleep apnea, transient arousal at the resumption of breathing is coincident with a substantial rise in blood pressure. To assess the hemodynamic effect of arousal alone, 149 transient stimuli were administered to five normal subjects. Two electroencephalograms (EEG), an electrooculogram, a submental electromyogram (EMG), and beat-to-beat blood pressure (Finapres, Ohmeda) were recorded in all subjects. Stimulus length was varied to produce a range of cortical EEG arousals that were graded as follows: 0, no increase in high-frequency EEG or EMG; 1, increased high-frequency EEG and/or EMG for < 10 s; 2, increased high-frequency EEG and/or EMG for > 10 s. Overall, compared with control values, average systolic pressure rose [nonrapid-eye-movement (NREM) sleep 10.0 +/- 7.69 (SD) mmHg; rapid-eye-movement (REM) sleep 6.0 +/- 6.73 mmHg] and average diastolic pressure rose (NREM sleep 6.1 +/- 4.43 mmHg; REM sleep 3.7 +/- 3.02 mmHg) over the 10 s following the stimulus (NREM sleep, P < 0.0001; REM sleep, P < 0.002). During NREM sleep, there was a trend toward larger blood pressure rises at larger grades of arousal (systolic: r = 0.22, 95% confidence interval 0.02–0.40; diastolic: r = 0.48, 95% confidence interval 0.31–0.62). The average blood pressure rise in response to the grade 2 arousals was approximately 75% of that during obstructive sleep apnea. Arousal stimuli that did not cause EEG arousal still produced a blood pressure rise (mean systolic rise 8.6 +/- 7.0 mmHg, P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals REDUCTION OF ARTERIAL BLOOD PRESSURE OF HYPERTENSIVE PATIENTS AND ANIMALS WITH EXTRACTS OF KIDNEYS

1941 ◽  
Vol 73 (1) ◽  
pp. 7-41 ◽  
Author(s):  
Irvine H. Page ◽  
O. M. Helmer ◽  
K. G. Kohlstaedt ◽  
P. J. Fouts ◽  
G. F. Kempf
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Malignant Hypertension ◽  
Hypertensive Rats ◽  
Hypertensive Patients ◽  
Arterial Blood ◽  
Lower Blood ◽  
Mean Pressure ◽  
Activity Loss ◽  
Experimental Stage

1. Extracts of kidneys have been prepared containing a substance which lowers arterial blood pressure for prolonged periods in patients with essential and malignant hypertension, and in hypertensive dogs and rats. 2. Several different chemical procedures are proposed for the preparation of the extract. The best one has not been decided upon. 3. The quantity of original fresh whole kidney required to yield enough extract to lower blood pressure from hypertensive levels (200 mm. Hg mean pressure) to normal levels is roughly 600 to 900 gm. in dogs within 4 to 8 days. In hypertensive patients the yield from 700 to 1000 gm. daily for several weeks may be necessary. 4. Lowering of the blood pressure too rapidly in animals results in a shock syndrome which may be fatal. If overdosage is avoided, no appreciable rise in blood urea nitrogen occurs, nor do other signs of toxicity appear. 5. Lowering of blood pressure to nearly normal levels has been accomplished in 60 hypertensive dogs, and in some of these it has been allowed to rise and was again reduced as many as five times. Similar results have been obtained with hypertensive rats. 6. Six patients with essential hypertension have been treated resulting in prolonged reduction of blood pressure. Clinically the patients appear improved. 7. Five patients with malignant hypertension have been treated, with reduction of the blood pressure in all instances. One patient was treated despite urea clearance of 5 per cent of normal. His blood pressure was sharply reduced, but death in uremia occurred. The second patient also exhibited sharp reduction of pressure and died after treatment was discontinued. The other three are much improved after treatment, as indicated by increase in vision and mental activity, loss of dyspnea, improvement in the electrocardiogram, etc. 8. The length of time the blood pressure remains lowered varies greatly in both animals and man. The trend is usually upwards after discontinuing treatment for 4 to 6 days. 9. Increasing experience with this treatment suggests that it is of value in the management of hypertension, but it is yet in the experimental stage.

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